Fire hazards associated with mattresses are well-known. Many individuals have been severely injured or have died in fires that started in, or were fueled by mattresses. Conventional mattresses typically contain a number of potentially volatile components that can ignite or fuel a fire. For example, the layer of ticking on a mattress is generally flammable, and can be ignited such as by a smoldering cigarette, a pipe, a cigar, a candle, a tipped over lamp, or a faulty electric socket. In addition, the foam within the mattress used for cushioning is combustible and may provide fuel for the fire. Pockets or cavities of air within the mattress provide oxygen for the combustion of mattress materials. Pillow-tops found on some mattress provide an additional layer of filling material that can be ignited. Moreover, the pillow-tops are typically set off from the mattress by gussets, which can create thin lines of highly volatile fill materials and add gaps and crevasses that can trap and concentrate the heat of the flames.
The springs found in traditional mattresses are normally held under compression by the mattress materials. However, once a fire consumes the external mattress materials, the springs may burst the mattress open and fully expose the flammable materials inside the mattress to the fire, thereby accelerating the fire. In addition, conventional methods of assembling mattresses produce seams that can split open and subject the internal cushioning material to the flames. The heat from the combustion of flammable mattress materials, such as, for example, the polyurethane foam cushioning material, produces noxious, toxic and/or combustible gases. As the temperature within the room rises, a “flashover” event may occur where the combustible gases ignite and engulf the entire room in flames.
Numerous attempts have been made to reduce the flammability of mattresses. One method has been to treat fabrics used in their construction with chemical flame retardants. However, chemical treatments may release undesirable odors and may cause skin irritation in some individuals. In addition, the chemical treatments may cause the fabric to be stiff and uncomfortable.
Another method is to form the mattress from non-flammable materials, such as, for example, certain forms of fiberglass. However, previously used forms of fiberglass may break over time. When these fibers break, they are very small and may not be removed from the linen simply by washing the bedding. Thus, once the fiberglass begins to break, the linen on the mattress will likely need to be replaced to remove the broken fibers. Flame resistant fibers or charring fibers such as silica modified rayon (Visil®), modacrylic, or melamine fibers can be produced in a batting or lofted material to provide flame resistance and insulation to the mattress. When a batting is used, as much as two times the fibrous batting required for cushioning the mattress is necessary to provide flame resistance. A mattress formed with this excess batting may be difficult to sew and manufacture, thus potentially raising the costs.
A further method to reduce the flammability of mattresses is to use specially constructed mattresses that have internally disposed elements such as liquid filled cells or non-flammable padding. However, such specially constructed mattresses are relatively high in cost.
Specific examples of attempts to fire-retard or fireproof mattresses are set forth below.
U.S. Pat. No. 3,670,348 to Irwin discloses the use of a fiberglass pad inside the ticking to enclose the combustible portion of the mattress. The fiberglass pad does not contain an organic binder. However, the fiberglass pad does not create a soft, comfortable surface. In addition, individual glass fibers may break off of the fiberglass pad and penetrate the surface of the mattress. These glass fibers may cause irritation and/or discomfort to the individual in contact with the mattress.
U.S. Pat. No. 3,818,521 to Richards discloses a heat conducting metallic foil positioned between the ticking and padding layers. The foil serves to prevent the flammable cloth ticking material from bursting into flame when the ticking is subjected to temperatures above which combustion would normally occur by conducting the heat away.
U.S. Pat. No. 4,092,752 to Dougan describes a mattress that has a core of a flame retarded polyurethane foam and an optional outer layer of a flexible polyimide foam. The foam core is enclosed in a flame retardant ticking. The box spring for use in conjunction with the flame retardant mattress has a non-combustible frame. The box spring may be padded with the same flame retarded polyurethane foam used in the mattress.
U.S. Pat. No. 4,430,765 to Karpen discloses a mattress that has a plastic impregnated water resistant ticking. The filling for the mattress is a cotton felt blended with a boric acid powder that will not support combustion under direct flame exposure.
U.S. Pat. No. 4,443,903 to Leitner describes a flame retardant composition that includes an aminophosphonate ester in combination with a thermosetting, nitrogen-containing resin. The composition preferably also contains a reactive elasatomeric latex.
U.S. Pat. No. 4,504,991 to Klancnik describes a mattress that includes a layer of a fire retardant material bonded (e.g., neoprene foam) to a layer of a high tensile strength material (e.g., fiberglass). When exposed to fire, the fire retardant material forms a char which creates a heat shield to protect the inside of the mattress from the flames.
U.S. Pat. No. 6,823,548 and U.S. Patent Publication No. 2004/0060120 to Murphy et al. disclose a composite barrier fabric that includes a fire barrier layer and a thermally insulating layer. Both the fire barrier layer and the thermally insulating layer include at least one flame retardant fiber. The composite barrier fabric is used to at least partially cover the core or filling of a mattress.
U.S. Patent Publication No. 2004/0226100 to Small, Jr. et al. describes a mattress that includes a core and a barrier material surrounding the core. The barrier material includes flame and heat resistant fibers such as glass, asbestos, modacrylic, carbon, polyphenylene, benzobisoxazole, melamines, and polyimides. Synthetic fibers such as polyester may be blended to improve strength and/or dimensional stability of the barrier material. The barrier material may also include an intumescent material.
U.S. Patent Publication No. 2005/0023509 to Bascom et al. describes a single layer nonwoven fabric for use as a fireblocking component in a mattress. The nonwoven fabric includes a cellulose fiber that retains at least 10% of its fiber weight when heated in air to 700° C. at a rate of 20° C. per minute (e.g., Visil®) and an organic fiber that retains 90% of its fiber weight when heated in air to 500° C. at a rate of 20° C. per minute (e.g., Kevlar®D fibers). The nonwoven fabric may also include a gassing material such as a modacrylic fiber or polyvinylchloride fibers.
U.S. Patent Publication No. 2005/0026528 to Forsten et al. discloses a fabric composite for use in fireblocking a mattress. The fabric composite includes a sacrificial outer ticking, a sacrificial cushioning material, and a fire-blocking fabric composed of a single layer of a nonwoven fabric. The nonwoven fabric is formed of a cellulose fiber that retains at least 10% of its fiber weight when heated in air to 700° C. at a rate of 20° C. per minute and a heat resistant fiber (e.g., Kevlar® fibers).
U.S. Patent Publication No. 2005/0095936 to Jones et al. describes a composite upholstery panel that includes a layer of ticking fabric, a layer of flame and heat resistant backing fabric, and a layer of resilient flame and heat resistant cushioning material positioned between the ticking and backing fabric. The cushioning material may be formed of flame resistant fibrous materials such as aramid, modacrylic, silica modified rayon, FR rayon, FR polyester, melamine carbon, and blends thereof. The backing layer may be formed of a fibrous material that has been treated with a flame retardant material. The ticking layer is a decorative layer of strong fabric and may be a knit or woven fabric formed from a flame resistant material or coated with a flame resistant material.
The high incidence of mattress fires throughout the United States has caused the formation of committees to establish standards for the testing flammability of mattresses. One example of these new standards to reduce flammability of mattresses used in homes is Assembly Bill 603 (TB 603) which was passed in the California Legislature Assembly and is incorporated herein by reference in its entirety. The bill requires that all mattresses and sleep surfaces sold in the state of California meet an open flame resistance standard as of Jan. 1, 2005. Other states are following California's example and have placed similar testing requirements before their legislatures. Although previous attempts to reduce flammability have, in some instances, been partly successful, there are few mattress that are capable of reducing flammability to a level that will meet the newest flammability standards, such as the open flame requirements of TB 603, and still meet desired comfort levels and cost restrictions.
Thus, there exists a need in the art for a mattress that meets the stringest flammability requirements, is low cost, and retains the comfort properties of traditional mattresses.